Beauty is in the eye of the beholder
by majorleeobvious
Summary: Rei had never been very fond of the concept of swimming, but all of that may change after meeting a certain blonde merman... (summaries are hard to write) Reigisa. Mermen AU. yaoi smut to come later, maybe?
1. Chapter 1

"Distance: 2.5 miles. Time: 22.4 minutes. Set distance to _d_. Set time to _t_. Rate is _r_. _R_ equals _d_ over _t_, or 8.96 minutes per mile. There are 60 minutes in an hour. Sixty divided by 8.96 equals approximately 6.7 miles per hour."

Rei mumbled calculations to himself as he performed his cool-down stretches in the shade of the tall rocks at the end of the beach. His time running on the sandy surface had significantly improved compared to when he first started, but it was still a long way from his target goal. Even though he had not joined the track team to compete, Rei didn't want to let down the senpais and coaches that had helped him so much this past semester. He had resolved to improve his time by at least a full minute.

Running on the beach did have its advantages—the loose sand had really helped build up and tone his calves—but Rei felt that the location may have been working against him. He looked out over the water and smiled. Beautiful. More than once, the blue-haired boy had caught himself unconsciously slowing his pace to better enjoy the view. Beautiful things were his weakness.

Reaching for his bag, Rei switched his running glasses for his regular red frames. Wiping his face, he gazed longingly at the crystal blue water. It probably felt great to cool off in the ocean after a run. After glancing at his watch and deciding he still had plenty of time before he had to get home, Rei climbed up onto the rocks near the end of the beach where the water was considerably deeper. He sat down on the edge of the largest flat rock and slipped off his running shoes. Gingerly dipping his feet into the water, Rei enjoyed the refreshing feeling of the ocean between his toes.

Lost in his thoughts, Rei didn't notice the soft pokes on his leg until a cool hand wrapped around his ankle and gently tugged.

"What the-?!" he cried, scrambling back away from the water. In his panic, his glasses had slipped off and fallen who knows where. Most likely into the ocean.

A blurry blonde head peeked over the rock and giggled. "Sorry, I didn't mean to scare you."

Rei squinted. The voice was presumably male, but rather high-pitched.  
"I wasn't scared!"

"You sounded pretty scared."

"I was not! I was just surprised. That's not the point though. Because of you, I lost my glasses. Ugh, they probably fell into the water."

The blurry figure waved something red over his head. "Ta-da!"

"My glasses!" Rei sat on his legs and reached out to grab them, but the boy swam just out of reach.

"Come and get them!"

"Hey!"

He swam out a bit further. "Just come over here."

"No!"

"Why not?"

Rei clenched his jaw shut. He didn't want to admit he couldn't swim. That went against his whole sense of beauty.

"Are you afraid of the water?"

"I'm not afraid!"

"Then come on."

"No!"

"Why not?"

"Because I can't swim dammit!"

"What?"

Rei cursed himself internally as he turned away to hide his blush.

The blonde swam back and looked up at him. "You don't know how to swim?"

The blue-haired boy moved to push up his glasses, remembered he wasn't wearing them, then balled up his hands in his lap. "No, I don't."

"Why?"

Rei's blush deepened and he tightened his fists. There was no way this rude and annoying blonde boy would understand the real reason why. Instead, he gave him the answer he gave everyone else. "Humans evolved to live on land, not swim in water."

Of course, he was the last person that should be claiming such things. As a pole vaulter, Rei spent most of his time trying to get away from the ground. The blonde boy planted his hands on either side of Rei's folded legs and pushed himself up to look him in the face.

"W-what?" stuttered Rei, increasingly uncomfortable with the boys close proximity.

"You're lying."

Rei blinked rapidly, trying to adjust his eyes. He was nearsighted, so with the blonde's closeness, he could see his face clearer. The boy had large eyes—a curious shade of dark pink. The blonde tilted his head and considered him for a moment before speaking.

"That's not the real reason, is it?"

Rei's eyebrows raised in surprise. The playful and cheery tone of the boy's voice had completely disappeared and was replaced with seriousness and concern. It was reminiscent of the way a counselor would talk to a troubled youth.

"Can I have my glasses back?" asked Rei, completely ignoring the blonde's question.

"Not until you tell me the real reason why you don't know how to swim."

The blue-haired boy looked down and muttered. "It's not beautiful."

"What?"

"It's not beautiful!" cried Rei, startling the boy and causing him to slip back down into the water. "A swimmer must flap his arms and legs underwater, while struggling to break the surface for a gasp of air. You can't look good while doing that! It defies reason!"

The blonde haired boy studied Rei for a moment before speaking. "Beauty shouldn't be the measure of something's worth."

His voice had a peculiar faraway quality that kept Rei silent. The blonde boy wordlessly pulled himself up to sit next to Rei and slipped his glasses back on. The blue haired boy studied him quietly. The boy was most likely around his age, but his face had a very cute, youthful quality to it. "Shota" he believed it was called. The dark pink eyes staring back at him reflected a jumble of emotions, but overall gave him the impression that the boy was eager, but shy about something.

As Rei shifted to slide his legs out from under him, he felt something cold and wet brush against his hand. He looked down and stared, wide-eyed, at the shiny tail sprouting from the blonde boy's lower half. Starting at what Rei could only assume were the boys hips was a long, magenta colored fish tail. When the light hit the scales at a certain angle, they got a rainbowy sheen, like opals.

The merboy looked down at his tail with a sad smile. "My tail lets me swim really fast. It helps me escape from predators in the water and to catch food. Even though it's not very pretty, it's still very important to me. You can't measure something's worth on beauty alone because even something as ugly as my tail is worth a lot."

"Beautiful."

The merboy looked up at Rei, surprised. "What?"

Very, very gently, the blue haired boy ran his fingertips over the tail. "It's beautiful."

The blonde blushed and shied away from the intimate gesture. Rei, sensing his discomfort—and feeling rather embarrassed himself—pulled his hand back and readjusted his glasses before speaking again.

"My name is Rei. Rei Ryugasaki. Nice to meet you."

"Rei-chan?"

"Rei-chan?!" he cried.

The merboy giggled—a sound Rei found himself enjoying much more than he should have at the particular moment.

"Nice to meet you Rei-chan. You can call me Nagisa."

He stared at Nagisa, ready to demand that he stop using the girly honorific, but after getting a good look at the merboy's smile, he could only look away and readjust his glasses once more.

"Hey Rei-chan, are your glasses broken?"

"No. Why do you ask?"

"Well, you keep pushing them up so I thought that maybe something loosened when they fell off."

"N-no, they're fine."

Nagisa peered into Rei's face. "Are you sure?"

Rei blushed. Readjusting his glasses was a habit he had developed some time around grade school. Whenever he was embarrassed, thinking about something really hard or just needed a moment to compose himself, he would use his whole hand to push up his glasses, effectively covering most of his face in the process.

"Yes I'm sure. Absolutely positive!"

The merboy leaned back and giggled again. "You're an interesting human Rei-chan."

The blue haired boy frowned. Something in that statement troubled him. Interesting? Interesting compared to whom?

"Have you met other humans then?"

Nagisa curled and uncurled his tail. "Yep, a few."

Rei's mouth set in a tight line. He stood up and brushed himself off. "It's getting late."

The merboy watched him with wide eyes. "You're leaving?"

The blue hared boy nodded wordlessly as he slipped on his shoes.

"Will you come again tomorrow?"

Rei glanced at the merboy for a moment and faltered. He wasn't sure if Nagisa was merely exaggerating, or if he really was about to cry. Either way, the thought of the blonde boy in tears if he refused was reason enough for Rei to agree.

"If you want me to come again, I can."

Nagisa's whole face lit up. "Really?!"

Rei nodded, adjusting his glasses.

"Hooray!" cried the merboy, throwing his arms up.

The blue haired boy had a slight sinking feeling that denying Nagisa anything in the future was going to be all but impossible. He picked up his bag and swung it over his shoulder. "I'll see you tomorrow then."

Nagisa smiled and nodded before sliding back into the water. He resurfaced a moment later and waved. "See you Rei-chan!"

With a flick of his tail, the merboy disappeared once again. As Rei looked out over the water, all he could think of was how the concept of swimming was staring to look a lot more inviting.

* * *

hello. this is my first serious attempt at writing a fanfiction of any sort so please forgive any mistakes and such. reigisa is my otp so i tried really really hard to keep them in character. if you're as big a free! fangirl as i am, you probably noticed i took some of rei's lines straight from episode 3. call it lazy, but the writers did a way better job explaining his thoughts on swimming than i ever could.

im thinking of writing a few more chapters for this and maybe add some yaoi smut (YAY SMUT!), but im not sure yet.

side note: if you like the concept of the free! boys as mermen, then i highly recommend you read "curiosity" by LawliPop. in fact, it was that fic and its sequel that inspired this. (it also contains a bunch of smutty goodness if you're into that kind of thing. i know i am)

anyway, i hope you enjoyed my sorry attempt at writing a fanfiction (or in the very least didn't see this as a complete waste of your time). any and all reviews are very much appreciated!


	2. Chapter 2

Rei had not been looking forward to his next meeting with Nagisa. Nope, not one bit. He had not stayed up all night researching merlore on the internet—and consequently woken up late and missed his morning run—because he wanted to know everything that he possibly could about the blonde merboy. Rei was just showing polite curiosity in the subject. He had also not spent nearly half an hour trying to pick out what to wear and end up settling on a new shirt and some shorts because he wanted to look particularly good. The blue haired boy just wanted to make sure he was dressed for the weather. Lastly, Rei had not stopped by the convenience store because he wanted to buy something for Nagisa. It was just a particularly hot day and he just happened to have enough money for two popsicles. Rei had absolutely not bought one specifically hoping that the merboy would like it. Not at all. Not one bit…

As Rei walked towards the end of the beach and tried to convince himself of the rationality of his actions, he pointedly ignored the butterflies fluttering in his stomach. He was not nervous; his stomach was probably just upset because he had eaten breakfast too quickly that morning.

By the time Rei sat on the rock where he had met Nagisa the day before, he almost believed himself. But as soon as he heard a familiar cry of "Rei-chan!" and felt a pair of wet and surprisingly strong arms wrap around his waist, all of his efforts sank to the bottom of the sea like a lead brick.

"N-Nagisa-kun! W-What—"

The merboy tightened his grip around the blue haired boy's waist. "I was worried you wouldn't come today."

Re turned away and fixed his glasses. "Of-of course I did. I said I would yesterday."

Nagisa mumbled into his shirt. "Not everyone is as honest as Rei-chan."

Before he could ask the blonde what he meant by that, Nagisa let go of him and sat down on the rock. "Oh no, I got your shirt all wet!"

Rei pulled on the places where the wet fabric had stuck to him. "It's fine."

"No, you should take it off" declared Nagisa, grabbing the hem and pulling up. "Humans are really delicate so you might catch a cold if you keep it on."

"It's nearly 100 degrees outside! I'm not going to catch a cold! And I am not delicate!" cried Rei, desperately trying to hold his shirt down.

"Better to be safe than sorry!" cried the merboy. With one final tug, Nagisa pulled off Rei's shirt and "accidentally" dropped it in the water.

"Oops."

"Nagisa-kun!"

The blonde fished it out of the water. "Oh no. Sorry Rei-chan. Well, you definitely can't wear it now."

Rei crossed his arms self-consciously. The enthusiasm with which Nagisa pursued something once the idea got in his head was starting to make the blue haired boy feel increasingly concerned on multiple levels. As he watched the merboy wring out the shirt and lay it out on a nearby rock to dry, Rei remembered the popsicles.

He pulled them out and handed one to Nagisa. "Here."

The merboy stared at the proffered plastic package, his eyes shining with curiosity. "What is it?"

Rei unwrapped the strawberry flavored one and handed it to Nagisa. "It's a popsicle."

"Pop…sicle?"

"It's flavored ice."

Nagisa took the popsicle and watched Rei unwrap his own and take a bite.

"It's going to melt if you don't eat it soon."

The merboy gathered his courage and took a bite. "Oh! It's good!"

Rei smiled as he watched him enthusiastically take large bites… "Wait, Nagisa-kun, you're eating it too f—"

"Oww, my head!"

"You got a brain freeze because you ate it too fast."

"Brain freeze?! It froze my brain?!" Nagisa frantically rubbed his head.

"Pfft, hahahahaha!"

"Rei-chan it's not funny! Do something!"

In between laughs, the blue haired boy explained to Nagisa that a "brain freeze" was just the colloquial name given to the headache caused by the dilating and swelling of blood vessels in the roof of the mouth when you ate something cold too quickly. After Rei assured him that it was not fatal, the merboy tentatively finished his popsicle.

"Thank you Rei-chan. It was really good, except for the freezing brain. That just hurt."

"You're welcome." Rei watched as Nagisa nibbled on the popsicle stick. "Nagisa-kun, do you like sweet things?"

The merboy nodded enthusiastically. "We don't have as many sweet things in the ocean as you humans do up on the surface, so they taste especially good to me."

Rei smiled. "It suits you."

"What does?"

"Liking sweet things."

"Why?"

"Because you're so cu—" Rei cut himself off as soon as he realized what he was saying.

"I'm what?"

"N-nothing" mumbled the blue haired boy, busying himself with picking up the garbage.

Nagisa cocked his head and watched closely as Rei set aside the plastic bag with the wrappers in it. "Rei-chan you have a hole in your stomach!"

"What?"

Rei gasped as Nagisa grabbed him by the waist and lowered his head to his navel. "Nagisa-kun, w-what are you-?!"

"There's a hole in your stomach!" cried the merboy, carefully trying to pinch Rei's bellybutton shut.

"It's not a hole, it's my bellybutton!" cried the blue haired boy, frantically trying to push Nagisa—who was getting uncomfortably close to delicate areas—off his lap.

"Bellybutton?"

As the merboy straightened up and placed his hand over his own completely smooth abdomen, Rei recalled one of the more confusing topics he had encountered in his "casual" research the night before. None of the articles and stories he had found agreed on how merpeople reproduced. Some likened them to dolphins or seahorses, while others claimed that their tails split into legs on the night of the full moon, and they mated like humans. Not that he had been especially interested in the topic or anything…

Rei was brought back from his musings by an inquisitive poke to his navel.

"What is it for?" asked Nagisa, once again engrossed in the odd indentation.

"It's a scar from where I was attached to my mother's umbilical cord."

"Un billing…cord?"

"Umbilical cord" repeated Rei, adjusting his glasses. "Just like any other mammal, humans are conceived and develop in the female's womb. All placental mammals have a navel, or bellybutton, it's just that it's especially noticeable in humans."

Nagisa absentmindedly pinched the skin on his abdomen. "Placental mammals…"

Rei held his glasses in place. "N-Nagisa-kun, if you don't have a bellybutton, then how does your kind…reproduce?"

"Hmm" the merboy leaned back and swayed his tail thoughtfully. "What's the word…plant…plat…plati…platypus! Like a platypus!"

"Platypus?"

"Yea, one of those funny looking animals with duck bills and beaver tails and fur. My friend Rin-chan says that the mommies lay eggs, but they feed their babies milk. We're kind of like that."

"Rin-chan?" For some reason, the name left an unpleasant taste in Rei's mouth.

"Yea, he lived in Australia for a few years, but he came back recently. He said that we weren't so weird because platypuses lay eggs even though they're technically mammals. We're technically mammals too."

"So, do you…m-mate like mammals, or like fish?"

Nagisa considered him for a moment, his eyes glittering with mischief. "Tell me how humans mate first."

"H-How…what?"

The merboy flicked his tail. "I'll tell you how merpeople mate, but only after you tell me how your kind does it."

Rei blushed up to his ears. He adjusted his glasses and tried to calm down. What the hell was he so embarrassed about? Nagisa was asking a perfectly justified question considering the topic they were discussing. A completely natural biological process. He'd learned plenty about it in his co-ed health class without batting an eyelash. This was no different at all.

"F-For humans, intercourse happens between a male and a female. The male inserts his penis into the females' vagina. When the male reaches orgasm, he ejaculates in the female. His sperm travels to the womb in order to try and fertilize the female's egg. If the egg is successfully fertilized, then the zygote embeds itself into the wall of the uterus. The zygote develops into an n embryo, then a fetus, and then, after 9 months, a baby is born."

Nagisa pouted and mumbled. "That wasn't sexy at all Rei-chan."

The blue haired boy's blush spread down to his neck. "W-What?!"

"Nothing" sing-songed the merboy with a coquettish grin.

Rei fought the urge to pull his legs up to his chest and hide his face in his knees. He had a growing suspicion that Nagisa enjoyed seeing him squirm, so he would say outrageous things on purpose.

"Well?" asked Nagisa impatiently.

Rei turned to him. "Well what?"

The merboy frowned and leaned toward him. "What about love?"

The blue haired boy blinked. "Love?"

"Yes. Love. You humans have it too don't you? Tell me about it."

Rei opened and closed his mouth, but no sound came out. For the first time in a very long time, he didn't have an answer. What was he supposed to say? Love was an unpredictable and messy emotion. There were no theorems, no equations, and no way to cleanly explain it.

After a moment, he cleared his throat. "Well, I've never experienced the emotion in a romantic context, so I'm probably not the best person to ask."

The merboy peered into his face. "Do you believe in true love Rei-chan?"

The blue haired boy felt his heartbeat quicken. Another question he didn't have an immediate answer to. He'd never really thought about love or romance. The idea of dating had never really crossed Rei's mind. Did he believe in true love?

"I…I'd like to."

Nagisa studied him for a moment before smiling and leaning back on his arms. Rei couldn't help but notice how lovely the merboy looked when he was genuinely smiling.

"I guess it's my turn now, isn't it?" asked Nagisa, tilting his head to the side.

Rei nodded and sat up a bit.

"Well, first off, we have 2 different types of mating: seasonal and enduring. Seasonal mating is when fertile people from all around travel to warmer waters for the purpose of preserving the species. It's quite animalistic of us, isn't it?"

The blue haired boy adjusted his glasses. "The desire to reproduce is instinctual."

Nagisa smiled. "Well, anyway, once my people reach a certain age, they are expected to go find a mate for the season and get to making babies. Sex is basically the same as you humans do it."

"The same?"

"Yep. Mating season happens during the period of the year when merpeople are most fertile, so changing from tail to legs is easier."

Rei sat up ramrod straight and looked at Nagisa incredulously. "L…Legs?"

The merboy nodded. "To mate, my people go on land and their tails split into legs because, as I'm sure you noticed, we don't exactly have dicks in this form."

Rei blushed.

"The mechanics of sex are the same as with humans. Anyway, after all the fun, you each go back home. If the female becomes pregnant, then she carries the baby for 6 months, lays the egg, sits on it for around 4 months, and then the baby hatches."

"Wait, so if the male and female part after mating, then does the child never know who its father is?"

"That's generally the case, but sometimes, mates are in the same pod so the daddy has a more active part in the kid's life. Merchildren are all raised communally, so parentage is really just a formality. You can always tell who you're related to though, even if you've never met before."

Rei sat back and absorbed the information. He was still stuck on the fact that Nagisa had the ability to change his tail into a pair of legs.

"It's all different if you have an enduring mate though."

"Enduring mate?"

The merboy nodded with a faraway smile. "A life partner. If you're lucky enough, you meet your destined one during the mating season. But most never meet at all."

The longing and loneliness in Nagisa's voice made Rei's chest tighten.

"When you find your enduring mate, you stop participating in the mating season. They are your one and only, so you can't bring yourself to change for someone else. Enduring mates can have sex whenever they feel like it without adhering to the mating season schedule because true love is stronger than primal instinct."

"It sounds nice" murmured Rei.

Nagisa ran his hand over his tail. "You know, even though seasonal mates are male and female, enduring mates don't have to be."

Fighting to control the mess of thoughts running through his head, Rei looked over at the merboy.

Nagisa held his gaze. "Enduring mates can be male and female, female and female, or male and male."

There was something there, and yet there wasn't. Was the blonde toying with him? Could he somehow sense Rei's inner turmoil and enjoyed making an even bigger mess of his thoughts than he already had?

The merboy slid off the rock and into the water, resurfacing a moment later. "Sorry, my scales were getting itchy."

"It's fine" said Rei, pushing up his glasses.

Nagisa swam up and held onto his legs. "Hey Rei-chan…do you want to learn how to swim?"

Two days ago, Rei would've said no and walked away. Two days ago, he would've scoffed at the sheer thought of himself splashing around in the ocean. Two days ago, he would've gone into a whole discourse on the absurdity of trying to move around in the water like a fish.

But two days ago, he hadn't met Nagisa.

"…ok."

* * *

hello again everyone and thank you for reading! i finally got around to writing the next chapter for this. sorry it took so long.  
so as you can see, i bumped up the rating to m because of nagisa and rei's colorful conversation. it took me a while to decide how i was going to do the whole mechanics of mermaid sex. i decided to just take the lazy and uncreative man's route and have them grow legs. (yes, i know it's a cop out)  
anyway, as you could probably tell, the whole purpose of this chapter was to get through technicalities so that i can concentrate on the smut in later chapters. (im probably going to have one more before the real fun begins)  
as always, reviews are very much appreciated and encouraged!


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